This application claims the priority of German application P 197 01 404.6-22 filed in Germany on Jan. 17, 1997, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a wheel-type landing gear for helicopters of the type having skid-type landing gear.
In the case of light helicopters, it is known and customary to use a sled as a landing gear which, for controlling the physical effects inherent to the helicopter, consists of skids and torsion tubes with a defined spring characteristic. This landing gear meets most operating requirements of a light helicopter but has significant disadvantages when the craft is moved on the ground. For improving the handling capabilities of the helicopter on the ground, removable wheels can be attached to the skids. Another possibility consists of providing a fixedly installed wheel-type landing gear which may also be constructed as a retracting landing gear.
However, these solutions have the disadvantage that, on the one hand, the heavy, bulky transport wheels must be available at the site; that is, must be carried along and that, on the other hand, the helicopter must be equipped with a cost-intensive wheel-type landing gear.
It has been implemented on a helicopter design (Bell 412EP) to fasten an undercarriage instead of the skid-type landing gear in the area of the landing gear fittings, in which case several measures must be carried out on the helicopter in order to ensure an additional support of the wheel-type landing gear and in order to provide embarking steps for the cabin crew. In addition, in the case of this known solution, it is required to arrange the main wheels at the level of the rear torsion tube (relative to the longitudinal axis of the helicopter) because otherwise it is not possible to introduce force.
It is an object of the present invention to provide an exchangeable wheel-type landing gear for a light helicopter which can be mounted on its fastening fittings instead of the skid-type landing gear without any special measures, a backfitting being possible at any time.
This object is achieved by providing wheel-type landing gear for helicopters, having fittings for a fastening on the helicopter which permit a receiving of the landing gear on the fittings intended for the fastening of a skid-type landing gear without any additional support of the helicopter, wherein said landing gear has two main wheels which are fastened to two rearward rocker arms which, by way of tube stubs by means of the two ends of a rearward cross tube are rotatably disposed such that the pivots are situated in the axis of the rearward cross tube so that the contact points of the main wheels are situated considerably behind the rearward fastening fittings, and wherein the rearward ends of two elastic embarking steps are fastened on the tube stubs in a torsion-proof manner by way of bearings, forward ends of the embarking steps projecting beyond forward fittings being fastened on the two ends of a cross member on which a rocker arm, which is constructed essentially in a V-shape, is rotatably disposed by means of its ends forming the upper end points of the V, its other end forming a nose wheel bearing and nose wheel.
The wheel-type landing gear further developed according to the invention represents an independent wheel-type landing gear which can be used without any change of the fastening fittings on the helicopter instead of the otherwise customary skid-type landing gear, a backfitting being possible at any time. Because of the further development according to the invention, the wheel-type landing gear has its own embarking step and has a wheel contact point of the main wheels which is clearly arranged behind the rearward cross tube.
This has the important advantage that the wheel-type landing gear according to the invention can be adapted to the respective position of the center of gravity without any change of the basic principle and without changing the fastening fittings on the helicopter, so that the required protection against a tilting beyond the rearward wheel contact point is ensured.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.